Most people just take pictures like this and then reproduce them on the restored car as close as possible to the origonal.

I can think of no reason to "clean up" and restore that part of the car. It never shows once assembled and leaving it alone it is a great way to keep original markings "original". It would be difficult to reproduce this one anyway. The crayon marks are so dried out after 40 years that they can wipe off like chalk where exposed. You can't reproduce OLD. The spray glue goes over the top of this mark and I have no idea how anyone could accurately reproduce the marks under the OEM stringy spray glue.